**4.3 Diagnostic test**

To check the existence of the multicollinearity issue, variance inflation factor (VIF), as an indicator of multicollinearity, is used. Multicollinearity test in the data set is performed and no multicollinearity problem is found in the data, as the VIF of variables is less than 10 (refer **Table 5**). Based on this, there is no concern of multicollinearity among the set of explanatory variables.
